It turns out that by at least one measure—the number of unforced errors—men play equally well throughout the match. They make unforced errors on about 30 percent of the most important points, about 30 percent of the least important, and about 30 percent of all those in between. But women show a very different pattern: 34 percent unforced errors on the least important points, steadily rising to almost 40 percent on the most important. That's almost surely too big a difference to be mere coincidence.

What, besides choking, could explain those numbers? Maybe the closest games are usually played late in the match, when players are more fatigued; maybe more of those games involve weak players; maybe more of them occur at the French Open, where the court is harder to play. But professor Paserman tests all these theories, and none stands up to statistical analysis.

Fascinating stuff, of course, but risky for any man to be writing about, particularly when you try to apply it to the business world, as he goes on to do.